What’s the story on chocolate?

chocolate and polyphenolsChocolate is big business, generating about $50 billion in annual worldwide sales. But is it good medicine? Before I get to that answer, let me give you some background on the manufacturing of chocolate.

The first use of chocolate appears to be about 3,000 years ago in Central Mexico to produce an intensely bitter drink called xocolatl. Today, we still get the raw material for chocolate from the seeds of the cocoa tree. However, now they are fermented and roasted prior to extracting the raw cocoa beans from their pods. The raw cocoa mass is then ground and heated to produce what is called chocolate liquor.

This chocolate liquid is exceptionally bitter because it is rich in polyphenols. This is what you get when you buy unsweetened baker’s chocolate. Keep in mind that even with the extreme bitterness of unsweetened baker’s chocolate, the total polyphenol content is only about 5 percent of the total mass (the rest is cocoa butter). This means that purified chocolate polyphenols are about 20 times bitterer than the taste of unsweetened baker’s chocolate.

The chocolate liquor can also be further refined. The most common way is to remove the fat portion (i.e., cocoa butter) from the chocolate liquor by simple pressing. What remains is the cocoa powder that retains all of the polyphenols but in a dry form that can be ground to a powder. The isolated cocoa butter is the base for making white chocolate. Although it is free of any of the beneficial polyphenols, it still retains the excellent mouth feel of the cocoa butter. Add some extra sugar, and it is a great-tasting snack that has absolutely no health benefits.

You can always add more sugar to the cocoa liquor to sweeten the chocolate taste. That’s the ”dark chocolate” that dominates the market today. Of course in the process, you dilute out the polyphenols, which give chocolate all of its health benefits, not to mention increasing calories and increasing insulin levels because of the added sugar. That’s why eating dark chocolate will not help you lose weight. When you add more sugar and milk to the dark chocolate, the bitter taste (and the health benefits) is even reduced further. Now you have a milk chocolate candy bar.

Now what about the health benefits of the chocolate polyphenols before you start diluting them out with added sugar? Here the research data are clear. If you consume enough chocolate polyphenols, you will reduce blood pressure (1). This is probably due to the increase of nitric oxide production and its beneficial effects on relaxing the endothelial cells that line the blood vessels (2). How much is enough? Over a two-week period about 500 mg of polyphenols per day (this is the amount found in a typical 100-gram bar of unsweetened baker’s chocolate) can significantly reduce blood pressure by about 4 mm Hg (3). If you are willing to consume smaller amounts of very dark chocolate (providing 30 mg of polyphenols per day) for a much longer period of time, there is an improvement in endothelial cell relaxation, but without a reduction of blood pressure (4). Therefore, the blood pressure benefits of chocolate consumption appear to be dose-related. There is also evidence of chocolate polyphenols having some anti-inflammatory properties (5).

Considering these benefits, should chocolate be considered a “super fruit”? To answer that question, a recent publication compared the ORAC (Oxygen Radical Absorption Capacity) values of unsweetened cocoa to similar-size servings of other fruit powders from “super fruits,” such as blueberries, pomegranate and acai berries (6). The ORAC value is a measure of the ability of the dried fruit to quench free radicals. The cocoa powder had a significantly higher ORAC value per serving than the other fruit powders. Before you get too excited, keep in mind that the typical cocoa powder in the supermarket has been treated with alkali (i.e. Dutch-treated) to remove much of the bitterness of the polyphenols and in the process remove most of their health benefits (6).

So if you want the health benefits of chocolate, just make it bitter (i.e. unsweetened baker’s chocolate) and eat a lot of it (about 100 grams per day). You won’t lose any weight, but your blood pressure will come down a bit. Now if you want some real anti-inflammatory benefits, eat the chocolate, take 2.5 grams of EPA and DHA and follow an anti-inflammatory diet. Now you have a far more powerful dietary approach for reducing cellular inflammation and its clinical consequences, such as elevated blood pressure.

References

1. Ried K, Sullivan T, Fakler P, Frank OR, and Stocks NP. “Does chocolate reduce blood pressure? A meta-analysis.” BMC Med 8:39 (2010)

2. Taubert D, Roesen R, Lehmann C, Jung N, and Schomig E. “Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide: a randomized controlled trial.” JAMA 298: 49-60 (2007)

3. Grassi D, Lippi C, Necozione S, Desideri G, and Ferri C. “Short-term administration of dark chocolate is followed by a significant increase in insulin sensitivity and a decrease in blood pressure in healthy persons.” Am J Clin Nutr 81: 611-614 (2005)

4. Engler MB, Engler MM, Chen CY, Malloy MJ, Browne A, Chiu EY, Kwak HK, Milbury P, Paul SM,Blumberg J, and Mietus-Snyder ML. “Flavonoid-rich dark chocolate improves endothelial function and increases plasma epicatechin concentrations in healthy adults.” J Am Coll Nutr 23: 197-204 (2004)

5. Selmi C, Cocchi CA, Lanfredini M, Keen CL, and Gershwin ME. “Chocolate at heart: The anti-inflammatory impact of cocoa flavanols.” Mol Nutr Food Res 52:1340-8 (2008)

6. Crozier SJ, Preston MG, Hurst JW, Payne JM, Mann J, Hainly L, and Miller DL. “Caco seeds are a super fruit,” Chemistry Central Journal 5:5 (2011)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

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About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.

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